Chronic diseases require administering of medicaments or drugs according to a predefined time schedule in order to keep the concentration level of a pharmaceutically active substance within given margins. Many medicaments require administration by way of infusion. Therefore, patients administering the medicament in self-medication typically make use of mobile infusion devices or pump devices, e.g. so called patch pumps. Such devices should be universally applicable and should be operable even by persons without formal medical training.
Moreover, such devices, like infusion pumps, should provide accurate, precise and reliable dosing and dispensing of the respective medicament. Typically, the medicament to be dispensed is provided in a disposable container, such as an ampoule or pouch. One type of patch pumps come in a modular design, e.g. comprising a disposable module comprising a reservoir and a reusable module comprising a pump mechanism. Once the medicament from the reservoir module is spent the device is decomposed, the empty reservoir module is disposed and a new reservoir module is reassembly with the reusable pump mechanism module. Another type of patch pumps come in a slightly different modular design. One module, the disposable module, comprising the reservoir and infusion mechanism the other module, the reusable module, comprising the control means for managing the pump's functions. As one example, the OmniPod system, comprises a reusable control module and a disposable module that does not contain medicament at once. Before the user attaches the disposable module to the infusion site, the reservoir is filled with medicament. The user, which, in most case will be the patient, has to withdraw medicament from a vial by means of a syringe and use this syringe to fill the reservoir through a fill port in the disposable module. This procedure, using a syringe to fill a reservoir of a mobile infusion device is well known in the art and used with different types of mobile infusion or pump devices.
For drug stability and sterility reasons the reservoirs of mobile infusion devices or pump devices, e.g. patch pumps, are delivered in an empty state. The medicament then has to be filled just before the reservoir is about to be used. Usually, a patient or a health care professional fills the reservoir with liquid medicament which comes in a vial or ampoule in a manner similar to what is described above.
However, from a safety and usability point of view this might not be the best solution as this procedure holds quite some risks. First the patient has to take care of the hygiene, ensuring that no contamination occurs during preparation of the syringe and during operating the syringe to first withdraw the liquid medicament and the dispense it into a reservoir. On top, he or she has to ensure that the medicament is the right medicament and correct concentration/dose and that the medicament is not deteriorated. Second, the patient has to make sure that the needle is put correctly into the filling port. Not correctly attaching the needle could for example lead to filling the medicament into the module body or housing instead of the reservoir. This would cause damage to the reservoir module and render it unusable. Another defect could be that the needle is inserted in a way that could damage the reservoir inside the module. Damaging the module could cause leaking of medicament during injection. In consequence, the patient would not be given the right dose or amount of medicament; however, no malfunction of the device is being detected. This seems to be a very critical risk. Third the patient needs to make sure that just about the right amount of medicament is filled. Overfilling may not only waste the precious medicament. It may also have a negative impact on the module's adhesive layer that is to ensure properly fixing the module to the body. Underfilling as the opposite, will cause the problem that the reservoir module is empty sooner as expected by the patient. This could get the patient in a precarious situation in case he or she does not have a replacement module or a refill ampoule and syringe at hand. Fourth the patient has to take care of needle stick injuries. Needle stick injuries constitute a severe risk in particular for health care professionals in view of diseases like, e.g., HIV, hepatitis B, asf. Fifth, a potential interruption during the filling procedure may endanger the whole process. The user might be interrupted by a phone call, some one ringing at the door, or some other incident catching his or hers attention. After returning the attention to the filling procedure the patient might find the syringe laying there for a couple of minutes. This could cause the risk of contamination, in particular when the syringe laid there unattendently. Sixth the user has to have the manual capabilities to handle syringes and ampoules in order to use this kind of devices. In particular withdrawing liquids from ampoules however requires some aptitude.
It is generally of importance, that the patient strictly follows a given prescription schedule. Therefore, it is necessary to have enough medicament at hand. However, as the medicament container is inside the pump device it may not be obvious for the user to ensure that the amount of medicament will be sufficient. Running out of medicine would put the patient of a chronic disease in a serious situation which may also be physically impacting.
It is therefore an object of the present invention to provide a filling device for a reservoir of a drug delivery device featuring an improved safety mechanism in order to minimize at least one of the risks associated with the filling procedure. It is a further object to provide intuitive and unambiguous support for a user in handling and/or to operating the drug delivery device when filling a liquid, e.g. medicament, into a reservoir of a drug delivery device. Furthermore, it is an objective to improve user comfort and safety in handling and/or operating the device. In particular, the invention serves to facilitate compliance with a given prescription schedule.